Acquisitions (Narrative) (Details) (USD $)	12 Months Ended		12 Months Ended		12 Months Ended					1 Months Ended	12 Months Ended			1 Months Ended	12 Months Ended			12 Months Ended					12 Months Ended			1 Months Ended	3 Months Ended	12 Months Ended				12 Months Ended
	Dec. 31, 2012 Podio [Member]	Apr. 30, 2012 Podio [Member]	Dec. 31, 2012 Bytemobile [Member]	Jul. 31, 2012 Bytemobile [Member]	Dec. 31, 2012 Netviewer AG [Member]	Dec. 31, 2011 Netviewer AG [Member]	Feb. 28, 2011 Netviewer AG [Member]	Feb. 28, 2011 Netviewer AG [Member] Product Related Technologies [Member]	Feb. 28, 2011 Netviewer AG [Member] Other Intangible Assets [Member]	Jul. 31, 2011 Cloud.com [Member]	Dec. 31, 2011 Cloud.com [Member]	Jul. 31, 2011 Cloud.com [Member] Product Related Technologies [Member]	Jul. 31, 2011 Cloud.com [Member] Other Intangible Assets [Member]	Oct. 31, 2011 ShareFile [Member]	Dec. 31, 2011 ShareFile [Member]	Oct. 31, 2011 ShareFile [Member] Product Related Technologies [Member]	Oct. 31, 2011 ShareFile [Member] Other Intangible Assets [Member]	Dec. 31, 2011 App-DNA [Member]	Nov. 30, 2011 App-DNA [Member]	Nov. 30, 2011 App-DNA [Member] Product Related Technologies [Member]	Nov. 30, 2011 App-DNA [Member] Other Intangible Assets [Member]	Mar. 31, 2011 Other Acquisition [Member]	Dec. 31, 2011 Ringcube [Member]	Mar. 31, 2012 Ringcube [Member]	Aug. 31, 2011 Ringcube [Member]	May 31, 2011 Kaviza, Inc. [Member]	Mar. 31, 2012 First Quarter [Member] Other 2012 Acquisitions, Private Company [Member]	Dec. 31, 2012 First Quarter [Member] Other 2012 Acquisitions, Private Company [Member]	Dec. 31, 2011 First Quarter [Member] Other 2012 Acquisitions, Private Company [Member]	Dec. 31, 2012 Second Quarter [Member] Other 2012 Acqusitions, Two Private Companies [Member]	Jun. 30, 2012 Second Quarter [Member] Other 2012 Acqusitions, Two Private Companies [Member]	Dec. 31, 2012 Third Quarter [Member] Other 2012 Acqusitions, Two Private Companies [Member]	Sep. 30, 2012 Third Quarter [Member] Other 2012 Acqusitions, Two Private Companies [Member]
Total consideration in business acquisitions		$ 43,600,000		$ 399,500,000			$ 107,500,000			$ 158,800,000				$ 54,000,000					$ 90,800,000			$ 10,500,000			$ 32,200,000		$ 24,600,000				$ 15,400,000		$ 5,300,000
Cash acquired in business combination		1,700,000		5,600,000			6,300,000			5,600,000				1,700,000					3,200,000						500,000		600,000				200,000
Acquisition transaction costs		500,000		2,100,000			3,100,000			2,900,000				700,000					1,300,000					500,000	600,000						400,000		200,000
Conversion of sock, stock units converted and assumed		127,668					99,100			288,742				180,697					114,487						58,439	33,301	13,481				66,459		13,487
Acquisition transaction costs expensed during period	500,000		2,100,000		1,100,000	2,000,000					2,900,000				700,000			1,300,000					600,000					400,000	100,000	400,000		200,000
Assets acquired	52,012,000		582,959,000
Intangible assets	24,600,000		248,900,000
Goodwill	25,473,000		225,344,000				98,700,000			98,300,000				49,300,000					57,700,000
Acquired Finite-lived Intangible Asset, Amount							28,800,000	3,200,000	25,600,000	89,000,000		58,000,000	31,000,000	28,200,000		16,000,000	12,200,000		44,800,000	36,700,000	8,100,000
Equity interest in subsidiary																										100.00%
Unvested stock options assumed in business acquisition																										88,687
Additional investment in the consolidated subsidiary																										$ 17,200,000
Stock options converted and assumed										183,780				390,775													12,017